u•ni•lat•er•alˌyu nəˈlæt ər əl(adj.)

1. relating to, occurring on, or involving one side only.

2. undertaken or done by or on behalf of one side, party, or faction only; not mutual:

   unilateral disarmament.

3. having only one side or surface; without a reverse side or inside, as a Möbius strip.

   Category: Math

4. Law. pertaining to a contract in which obligation rests on one party only.

   Category: Law

5. Bot. having all the parts disposed on one side of an axis, as an inflorescence.

   Category: Common Vocabulary

6. through forebears of one sex only, as through either the mother's or father's line.

   Category: Anthropology

   Ref: Compare bilateral (def. 5). 5

Origin of unilateral:

1795–1805; < NL ūnilaterālis. See uni -, lateral

u`ni•lat′er•al•ly(adv.)